The ability of the mussels to quickly colonize new areas, rapidly achieve high densities and attach to any hard substratum (e.g., rocks, logs, aquatic plants, shells of native mussels, exoskeletons of crayfish, plastic, concrete, wood, fiberglass, pipes made of iron and polyvinyl chloride and surfaces covered with conventional paints) make it possible for them to cause serious adverse consequences. These consequences include damages of water-dependent infrastructure, millions of dollars increase in the operating expense and significant damage to the ecological systems.
Management of mussels is very important for protecting water-dependent infrastructure and aquatic ecological systems. There are many proactive and reactive methods to control and reduce the populations of mussels. Reactive removal includes the mechanical removal, predator removal, and chemical and biochemical removal of adult mussels. For example, fish, birds, crayfish, crabs, leeches and mammals have shown to predate mussels. However, it is unlikely that invasive mussel populations will be controlled by natural predation, especially in man-made structures such as pipes or pumping plants. Proactive measures to control mussels includes any mechanical, physical or chemical means in witch the planktonic (veliger) mussel life stage is prevented from settling and growing into the adult life stage or colonizing on hard substrates. Preventing mussels from colonizing and growing into adult life stages is also referred to as settlement prevention.
Molluscicides
Exploitation of environmentally friendly biopesticides for effective control of invasive mussels is crucial to avoid water resources from damage of harmful chemicals. To reach such a goal, more than 700 bacterial isolates were screened as potential biological control agents to be used against zebra and quagga mussels from New York State Museum's (NYSM) Field Research Laboratory. One of these strains, Pseudomonas fluorescens (CL 145A), was found to be lethal to these mussels (see Molloy, D. P. U.S. Pat. No. 6,194,194, issued Feb. 27, 2001). This bacterium is worldwide in distribution and is present in all North American waterbodies. In nature it is a harmless bacterial species and found to protect the roots of plants from rot and mildew. It is so ubiquitous that it is a common food spoilage organism in the average household refrigerator [Daniel P. Molloy and Denise A. Mayer, Overview of a Novel Green Technology Biological Control of Zebra and Quagga Mussels with Pseudomonas fluorescens, Version 6: Updated Aug. 24, 2007]. This strain has also been found to be active against golden mussels (see PCT appln. pub. No. WO2012/065038) and various fungi and bacteria (see PCT appln. no. PCT/US2013/028112). Lactones and fatty acids were found as active ingredients (US Patent Appln Pub. No. US20100266717A1). However, quantity and mussel toxicity of such active ingredients could not explain of the mussel toxicity of the whole bacterium.
Fumarate Hydratase
Fumarate hydratase, an enzyme, is also called fumarase, L-malate hydrolyase or (S)-malate hydrolyase. Its main function is to catalyze the reversible hydration/dehydration of fumarate to malate. This enzyme is in mitochondrial and cytosolic. The mitochondrial isoenzyme is involved in the Krebs Cycle (also known as the Tricarboxylic Acid Cycle [TCA] or the Citric Acid Cycle), and the cytosolic isoenzyme is involved in the metabolism of amino acids and fumarate. In the citric acid cycle, it facilitates a transition step in the production of energy in the form of NADH. In the cytosol, it metabolizes fumarate, which ends up as a byproduct of the urea cycle as well as amino acid catabolism. In plants, it functions as reductive citric acid cycle (CO2 fixation), and in mammals it is involved in renal cell carcinoma.
Depending on the arrangement of their relative subunit, their metal requirement, and their thermal stability, fumarases can be classified into two classes (I & II). Class I fumarases are able to change state or become inactive when subjected to heat or radiation, are sensitive to superoxide anion, are Iron II (Fe2+) dependent, and are dimeric proteins consisting of around 120 kD. Class II fumarases, found in prokaryotes as well as in eukaryotes, are tetrameric enzymes of 200,000 D that contain three distinct segments of significantly homologous amino acids. They are also iron-independent and thermal-stable. Prokaryotes are known to have three different forms of fumarase: fumarase A, fumarase B, and fumarase C. fumarase C is a part of the class II fumarases, whereas fumarase A and fumarase B from Escherichia coli (E. coli) are classified as class [Estévez M, Skarda J, Spencer J, Banaszak L, Weaver TM (June 2002). “X-ray crystallographic and kinetic correlation of a clinically observed human fumarase mutation”. Protein Sci. 11(6): 1552-7].
Fumarases have been found to play a role in a number of metabolic disorders. For example, benign mesenchymal tumors of the uterus, leiomyomatosis and renal cell carcinoma, and fumarase deficiency are related to fumarase mutation and development. It is also related to fetal brain abnormalities [reviewed in Deschauer M, Gizatullina Z, Schulze A, Pritsch M, Knoppel C, Knape M, Zierz S, Gellerich F N. Molecular and biochemical investigations in fumarase deficiency. Mol Genet Metab. 2006 June; 88(2):146-52. Epub 2006 Feb. 28.] Except for these functions, whether there is an additional function, especially in mussel, is unknown.
Dihydrolipoamide Dehydrogenase
Dihydrolipoamide dehydrogenase, a mitochondrial enzyme, is also called dihydrolipoyl dehydrogenase. It degrades dihydrolipoamide and produces lipoamide. It is a part (a subunit) of several enzyme complexes (groups of enzymes that work together). These complexes are essential for the breakdown of certain molecules to produce energy in cells. Dihydrolipoamide dehydrogenase forms a subunit called the E3 component that is shared by several enzyme complexes including pyruvate dehydrogenase complex, 2-oxo-glutarate complex, branched chain keto acid dehydrogenase complex. Deficiency of E3 component will be involved in human diseases such as maple syrup urine disease [Shaag A et al. (1999). “Molecular basis of lipoamide dehydrogenase deficiency in Ashkenazi Jews.” Am. J. Med. Genet. 82(2):177-82.]. Except for these functions, whether there is an additional function, especially in mussel, is unknown.